9 Managing Usage Tracking

This chapter describes how to manage usage tracking for Oracle Business Intelligence. The Oracle BI Server supports the collection of usage tracking data. When usage tracking is enabled, the Oracle BI Server collects usage tracking data for each query and writes statistics to a usage tracking log file or inserts them directly to a database table. It is strongly recommended that you use direct insertion instead of writing to a log file.

9.1 About Usage Tracking

The Oracle BI Server supports the accumulation of c. The BI Server tracks usage at the detailed query level.

When you enable usage tracking, statistics for every query are inserted into a database table or are written to a usage tracking log file. If you use direct insertion, then the BI Server directly inserts the usage tracking data into a relational database table. It is recommended that you use direct insertion to write statistics to a database table.

When the BI Server starts, it validates the column names in the metadata against the list of valid columns in the usage tracking table. The following events occur:

Column names. If there is a mismatch between the columns in the database table and the columns in the metadata, then it results in a database error on insert.

Varchar length. If the length in the metadata and the set length in the table do not match, then an error is written to the nqserver.log file and usage tracking is disabled.

Note:

A sample usage tracking implementation is provided with the Oracle Business Intelligence installation at:

9.2.1 Setting Up the Usage Tracking Statistics Database

Before you can use direct insertion usage tracking, you must set up a database to store the usage tracking statistics. You must run the Repository Creation Utility (RCU) on the target database to create the required statistics schema.

Typically, you use the database you installed for use with Oracle Business Intelligence as the statistics database because this database already has the RCU-created schemas. The RCU-created table name for usage tracking is S_NQ_ACCT.

You also need to import the database into the Physical layer of the Oracle BI repository.

To set up the usage tracking statistics database:

Run the Repository Creation Utility on an external database of your choice. You can skip this step if you choose to use the database you installed for use with Oracle Business Intelligence for usage tracking statistics, because this database has the RCU-created tables already.

Ensure that the UsageTrackingCentrallyManaged attribute is set to true. When UsageTrackingCentrallyManaged is set to false, the following parameters are managed using the NQSConfig.INI file on each Oracle BI Server computer rather than the System MBean Browser:

SummaryAdvisorTableName

SummaryStatisticsLogging

UsageTrackingConnectionPool

UsageTrackingDirectInsert

UsageTrackingEnabled

UsageTrackingPhysicalTableName

Set the UsageTrackingEnabled attribute to true to enable usage tracking.

Set the UsageTrackingDirectInsert attribute to true to enable direct insertion.

Set the UsageTrackingPhysicalTableName attribute to the name of the fully-qualified database table for collecting query statistic information, as it appears in the Physical layer of the Oracle BI repository. For example:

"My_DB"."DEV_BIPLATFORM"."S_NQ_ACCT"

Set the UsageTrackingConnectionPool attribute to the name of the fully-qualified connection pool for the query statistics database, as it appears in the Physical layer of the Oracle BI repository. For example:

"My_DB"."Usage Connection Pool"

Note:

For Usage Tracking insertions to succeed, the connection pool must be configured with a user ID that has write access to the back-end database. Also, it is recommended that the connectivity type supports international data.

After applying your changes, release the lock on the domain, as follows:

Return to the BIDomain MBean where group=Service under oracle.biee.admin, Domain:bifoundation_domain, BIDomain.

Display the Operations tab.

Click one of the commit operations.

Go to the Oracle Business Intelligence Overview page and click Restart.

For upgrading customers, the usage tracking parameters are not centrally managed by default. You can set UsageTrackingCentrallyManaged to true as described in the previous procedure, and use the System MBean Browser to update the parameters, or you can manage the usage tracking parameters using NQSConfig.INI.

To enable direct insertion usage tracking in NQSConfig.INI when central management is disabled for these parameters, follow these steps:

On the Oracle BI Server computer, open the NQSConfig.INI file in a text editor. You can find this file at:

ORACLE_INSTANCE/config/OracleBIServerComponent/coreapplication_obisn

Make a backup copy of the file before editing.

In the [USAGE_TRACKING] section, update the following parameters:

Set ENABLE to YES.

Set DIRECT_INSERT to YES.

Set PHYSICAL_TABLE_NAME to the name of the fully-qualified database table for collecting query statistic information, as it appears in the Physical layer of the Oracle BI repository. For example:

PHYSICAL_TABLE_NAME = "My_DB"."DEV_BIPLATFORM"."S_NQ_ACCT";

Set CONNECTION_POOL to the name of the fully-qualified connection pool for the query statistics database, as it appears in the Physical layer of the Oracle BI repository. For example:

CONNECTION_POOL = "My_DB"."Usage Connection Pool";

Note:

For Usage Tracking insertions to succeed, the connection pool must be configured with a user ID that has write access to the back-end database. Also, it is recommended that the connectivity type supports international data.

Save and close the file.

Restart the Oracle BI Server.

If you have multiple Oracle BI Server instances, then repeat these steps in each NQSConfig.INI file for all Oracle BI Server instances.

9.2.3 Setting Optional Direct Insert Parameters

In addition to the setup parameters described previously, you can also update the following optional parameters in the Usage Tracking section of the NQSConfig.INI file:

BUFFER_SIZE. This parameter indicates how much memory the BI Server should allocate for buffering the insert statements. Such a buffer lets the BI Server submit multiple insert statements as part of a single transaction, improving Usage Tracking insert throughput. It also means that ordinary analyses do not have to wait on Usage Tracking insertions, which improves average query response time. You might want to adjust this value based on available memory and memory utilization on the server computer.

BUFFER_TIME_LIMIT_SECONDS. This parameter indicates the maximum amount of time that an insert statement remains in the buffer before the Usage Tracking subsystem attempts to issue it. This time limit ensures that the BI Server issues the insert statements quickly, even during periods of extended quiescence.

NUM_INSERT_THREADS. This parameter indicates the number of threads that remove insert statements from the buffer and issue them to the Usage Tracking database. Assuming separate connection pools for readers and inserters, the number of insert threads should typically equal the Maximum Connections setting in the connection pool.

MAX_INSERTS_PER_TRANSACTION. This parameter indicates the maximum number of insert statements that the Usage Tracking subsystem attempts to issue as part of a single transaction. The larger this number, the greater potential throughput for UsageMarathon Tracking inserts. However, a larger number also increases the likelihood of transactions failing due to deadlocks. A small value for BUFFER_TIME_LIMIT_SECONDS can limit the number of inserts per transaction.

The following sections explain how to configure log file collection for usage tracking. Before you configure the log file parameters, you must set the ENABLE parameter in the Usage Tracking section of the NQSConfig.INI file to YES (or set the UsageTrackingEnabled attribute of the BIDomain.BIInstance.ServerConfiguration MBean to true using the System MBean Browser, if central management of usage tracking is enabled). See Appendix A, "NQSConfig.INI File Configuration Settings" for more information about the usage tracking configuration parameters.

9.3.1 Selecting an Output Location

The STORAGE_DIRECTORY parameter in the Usage Tracking section of the NQSConfig.INI file determines the location of usage tracking log files. If usage tracking is enabled, but no storage folder is specified, then the files are written in the logs folder in the software installation folder (for example, in \OBI11g\logs).

Current files are periodically written to disk, and new files are created. The CHECKPOINT_INTERVAL_MINUTES parameter controls the frequency with which usage tracking data is flushed to disk, and the FILE_ROLLOVER_INTERVAL_MINUTES parameter controls the frequency with which the current usage tracking log file is closed and a new file is created.

When usage tracking is enabled, every query is logged to a usage tracking log file. This might require a large amount of available storage. For example, assume an average of 300 bytes of data output for each query and 10 queries per second over an 8 hour day. This results in approximately 83 MB of usage tracking data that is written to storage per day. If this example is extended to a 24 x 7 operation, then the result is approximately 0.25 GB of storage per day.

The BI Server has no limit on the size or quantity of usage tracking log files that can exist in the specified location. You must ensure that sufficient space is available and that you remove or archive old usage tracking files.

Caution:

Insufficient storage space might cause you to lose usage tracking data. If the BI Server encounters an error while accessing a usage tracking output file, then it immediately discontinues the collection of usage tracking statistics and issues an error message to the nqserver.log and, on Windows, to the Windows Event log. Even if additional storage space is made available, the collection of usage tracking statistics does not resume until the server is restarted.

9.3.2 File Naming Conventions

The file naming scheme for the usage tracking log files is NQAcct.yyyymmdd.hhmmss.log, where yyyy is the year, mm is the month, dd is the day, hh is the hour, mm is the minute, and ss is the second of the timestamp when the file was created. For example, if the server creates the usage tracking log file at 07:15:00 a.m. on February 12, 2010, the file name would be NQAcct.20100212.071500.log. After the specified rollover interval, this file is flushed to disk and closed and a new log file, with the current date and timestamp, is created.

9.3.3 Output File Format

The usage tracking log files are text files, in semicolon-delimited ( ; ) format. A semicolon is used as the column delimiter because the logical SQL text contains commas. A line feed delimits the end of each row of data.

Although there is no guaranteed unique key for the usage tracking data, a combination of User name, Node ID, Start timestamp, and Query text is usually sufficient. Query_Key can be used as an unique key but Query_Key is available only in direct insert.

Table 9-1 describes the schema. The following list contains more detail about Integer data types and Timestamp columns:

Integers data types. All data in the output file is in character format. The data in columns 12 through 18 are output as text representations of integer numbers. Therefore, they behave more like Varchar(10) columns than integers. For example, if the row count is one million rows, then 1000000 appears in the output file in column 13 (Row count). This constitutes 7 bytes of data, even though the data represents a 4-byte internal integer value.

In column 12, a Success indicator value of 0 signifies a successful query. All nonzero values indicate failure. The following failure indicators are currently defined:

1 indicates timeout

2 indicates row limit violation

3 indicates unknown error

The subsequent integer columns are valid only if the Success indicator (column 12) signifies a successful query (value is 0):

Timestamp columns. The Start timestamp and End timestamp columns indicate the wall clock time (local time) when the logical query started and finished. Each value is 19 bytes of character data that represents a SQL-92 timestamp. The format is yyyy-mm-dd-hh:mm:ss. The related columns, Start date and End date, contain just the date component from the respective timestamps (in the yyyy-mm-dd format). Finally, the related columns, Start hourMin and End hourMin, contain just the hour and minute components from the respective timestamps (in a char hh:mm format).

9.3.4 Performance Considerations

When usage tracking is enabled, the BI Server collects usage tracking data for every query. This data, however, is written to disk only at user-specified intervals, known as checkpoints. The default setting is to have checkpoints every 5 minutes.

Although you can modify this value in the NQSConfig.INI file, reducing the interval adds overhead and, if set low enough, could potentially impact server performance. Setting the value to a larger number increases the amount of usage tracking data that could be lost in the unlikely event of an abnormal shutdown of the BI Server.

The BI Server periodically initiates usage tracking log file rollovers. A rollover consists of closing the current usage tracking log file and opening a newly created one for writing subsequent data. The frequency at which rollovers occur is called a rollover interval. The default rollover interval is 240 minutes (every 4 hours).

Usage tracking log files that are closed are available for analysis. Setting a lower rollover interval makes usage tracking log files available for analysis sooner, but at the cost of additional overhead.

If the checkpoint interval equals or exceeds the rollover interval, then only the rollover occurs explicitly. The checkpoint occurs implicitly only when the old usage tracking log file is closed.

9.4 Description of the Usage Tracking Data

Table 9-2 describes each column in the S_NQ_ACCT usage tracking table. Where appropriate, the data type and length is also included.

As you review the descriptions in Table 9-2, you might assume that certain of the time-related columns can be added or subtracted to equal exact values. For example, you might assume that TOTAL_TIME_SEC is equal to END_TS minus START_TS. The following list explains why the columns do not provide such exact values:

The various processes run in parallel and their speed depends on the load on the BI Server and on database performance. The server-based operations might be either light or intensive.

If all connections are full, then the query enters a queue and waits to be processed. The timing depends on the load and configuration of the BI Server.

Table 9-2 Usage Tracking Data in S_NQ_ACCT

Column

Description

CACHE_IND_FLG

Default is N.

Y indicates a cache hit for the query; N indicates a cache miss.

COMPILE_TIME_SEC

The time in seconds that is required to compile the query. The number for COMPILE_TIME_SEC is included in TOTAL_TIME_SEC, as described in this table.

CUM_DB_TIME_SEC

The total amount of time in seconds that the BI Server waited for back-end physical databases on behalf of a logical query.

CUM_NUM_DB_ROW

The total number of rows that are returned by the back-end databases.

END_DT

The date the logical query was completed.

END_HOUR_MIN

The hour and minute the logical query was completed.

END_TS

The date and time the logical query finished. The start and end timestamps also reflect any time that the query spent waiting for resources to become available.

Note: If the user submitting the query navigates away from the page before the query finishes, then the final fetch never happens, and a timeout value of 3600 is recorded. However, if the user navigates back to the page before the timeout, then the fetch completes at that time, and this is recorded as the end_ts time.

ERROR_TEXT

Default is Null. Varchar(250)

Error message from the back-end database. This column is only applicable if the SUCCESS_FLG (for more information, see entry later in this table) is set to a value other than 0 (zero). Multiple messages are concatenated and are not parsed by the BI Server.

NODE_ID

The host name of the computer where the BI Server is running.

NUM_CACHE_HITS

Default is Null. Number(10,0).

For DB2, the data type and length is Decimal(10,0).

Indicates the number of times that the cache result returned for query.

NUM_CACHE_INSERTED

Default is Null. Number(10,0).

For DB2, the data type and length is Decimal(10,0).

Indicates the number of times that the query generated a cache entry.

NUM_DB_QUERY

The number of queries that were submitted to back-end databases to satisfy the logical query request. For successful queries (SuccessFlag = 0) this number is 1 or greater.

PRESENTATION_NAME

Default is Null. Varchar(128)

The name of the Oracle BI Presentation Catalog.

QUERY_BLOB

The data type is ntext when using SQLServer, and is CLOB when using ORACLE, DB2, or TERRADATA databases.

Contains the entire logical SQL statement without any truncation.

QUERY_KEY

Default is Null. Varchar(128).

An MD5 hash key that is generated by Oracle Business Intelligence from the logical SQL statement.

QUERY_SRC_CD

The source of the request (for example, Drill or Report).

QUERY_TEXT

Varchar(1024).

The SQL statement that was submitted for the query.

You can change the length of this column (using the ALTER TABLE command), but note that the text that is written into this column is always truncated to the size that is defined in the physical layer. It is the responsibility of the repository administrator not to set the length of this column to a value greater than the maximum query length that is supported by the back-end physical database.

For example, Oracle Databases enable a maximum Varchar of 4000, but Oracle Databases truncate to 4000 bytes, not 4000 characters. Hence, if you use a multibyte character set, the actual maximum string size has a varying number of characters, depending on the character set and characters used.

REPOSITORY_NAME

The name of the repository that the query accesses.

ROW_COUNT

The number of rows that are returned to the query client.

Note: When a large amount of data is returned from a query, this column is not populated until the user displays all of the data.

IMPERSONATOR_USER_NAME

Default is Null. Varchar(128)

The user name of the impersonated user. If the request is not run as an impersonated user, then the value is NULL.

SAW_DASHBOARD

The path name of the dashboard. If the query was not submitted through a dashboard, then the value is NULL.

SAW_DASHBOARD_PG

Default is Null. Varchar(150)

The page name in the dashboard. If the request is not a dashboard request, then the value is NULL.

SAW_SRC_PATH

The path name in the Oracle BI Presentation Catalog for the analysis.

START_DT

The date that the logical query was submitted.

START_HOUR_MIN

The hour and minute that the logical query was submitted.

START_TS

The date and time that the logical query was submitted.

SUBJECT_AREA_NAME

The name of the business model that is being accessed.

SUCCESS_FLG

The completion status of the query, as defined in the following list:

0 - The query completed successfully with no errors.

1 - The query timed out.

2 = The query failed because row limits were exceeded.

3 = The query failed due to some other reason.

TOTAL_TIME_SEC

The time in seconds that the BI Server spent working on the query while the client waited for responses to its analyses. TOTAL_TIME_SEC includes the time for COMPILE_TIME_SEC.

Table 9-3 describes the S_NQ_DB_ACCT table, which supplements the usage tracking table by providing the physical SQL information for the logical queries stored in S_NQ_ACCT. S_NQ_DB_ACCT has a foreign key relationship back to S_NQ_ACCT.

Table 9-3 Usage Tracking Data in S_NQ_DB_ACCT

Column

Description

END_DT

The date the physical query was completed.

END_HOUR_MIN

The hour and minute the physical query was completed.

END_TS

The date and time the physical query finished. The start and end timestamps also reflect any time that the query spent waiting for resources to become available.

ID

The unique row ID.

LOGICAL_QUERY_ID

Varchar2(50).

Refers to the logical query in the S_NQ_ACCT table.

QUERY_BLOB

The data type is ntext when using SQLServer, and is CLOB when using ORACLE, DB2, or TERRADATA databases.

Contains the entire physical SQL statement without any truncation.

QUERY_TEXT

Varchar(1024).

The SQL statement that was submitted for the query.

ROW_COUNT

The number of rows that are returned to the query client.

TIME_SEC

The physical query execution time.

START_DT

The date that the physical query was submitted.

START_HOUR_MIN

The hour and minute that the physical query was submitted.

START_TS

The date and time that the physical query was submitted.

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